Answer:
[tex]C \approx 91.732^{\circ}[/tex]
Step-by-step explanation:
(This exercise is presented in Spanish and for that reason explanation will be held in such language)
El lado restante se determina por la Ley del Coseno:
[tex]a = \sqrt{b^{2}+c^{2}-2\cdot b\cdot c \cdot \cos A}[/tex]
[tex]a = \sqrt{5.79^{2}+10.4^{2}-2\cdot (5.79)\cdot (10.4)\cdot \cos 54.46^{\circ}}[/tex]
[tex]a \approx 8.466[/tex]
Finalmente, el angulo C se halla por medio de la misma ley:
[tex]\cos C = - \frac{c^{2}-a^{2}-b^{2}}{2\cdot a \cdot b}[/tex]
[tex]\cos C = -\frac{10.4^{2}-8.466^{2}-5.79^{2}}{2\cdot (8.466)\cdot (5.79)}[/tex]
[tex]\cos C = -0.030[/tex]
[tex]C \approx 91.732^{\circ}[/tex]